The proposal expresses the applicant's interest in that area of science in which dentistry and its needs interface with physics and chemistry, particularly surface physical chemistry and polymer chemistry. The proposal first attempts to present a rather diverse background taken from the author's own work; from the physical chemical aspects of caries and the various means which have been attempted for caries control; from polymer chemistry, polyelectrolyte and ion-exchange technology; and from other related areas of the dental and physical sciences. The applicant's major contribution to dentistry has been the development of a means of diagnosing very early incipient caries. The method operates through the rapid uptake of a fluorescent solution by the greater porosity associated with developing caries. It depends upon water-displacement and capillary effects to permeate and infiltrate lesions and leave behind an organic fluorescent indicator. In preliminary exploratory experiments this investigator has demonstrated that the methods and technology underlying the caries-diagnostic technique can be carried over to the development of a caries-therapeutic treatment which will operate by the deposition of polymer materials inside developing, incipient, carious lesions. Two approaches are discussed: In one, the idea is to deposit a polymer barrier which will act to limit or prevent further intrusion of caries-promoting acids and bacteria. The barrier will act analogously to a fissure sealant. In the other approach, the idea is to deposit an ion-exchange polymer which will act as a source of flouride and hydrogen fluoride for long-term, low-level release at the site of an incipient lesion. The problems and the potential associated with these ideas, and methods for investigating and reducing them to practical treatment systems, are discussed in detail.